BUENOS AIRES—Choosing safety and security in a time of uncertainty, the International Olympic Committee voted to bring the 2020 Summer Games to Tokyo.

Tokyo carried the day over rivals Istanbul and Madrid by convincing the committee it could best guarantee a successful Olympics. The vote will bring the Olympics back to Tokyo for the first time since 1964, when the Games helped Japan reintroduce itself to the world less than two decades after the end of World War II.

The decision means that the Far East will become the center of the Olympic movement toward the end of this decade. The 2018 Winter Games are scheduled for Pyeongchang, South Korea.

Japan Celebrates

People celebrate as Tokyo wins the host city of the 2020 Olypics at the live-viewing event in Tokyo. AFP/Getty Images

The Finalist Cities

The International Olympic Committee chose Tokyo as the host city for the 2020 Summer Games. Madrid and Istanbul were the two other final contenders.

Related Reading

"In these uncertain times, we must make this a Games that can be delivered," said a triumphant Masato Mizuno, chief executive of the Tokyo2020 bid.

Tokyo nearly won on the first ballot, garnering 42 of 94 votes, falling just six short of the majority needed for victory. In that ballot, Madrid and Istanbul tied at 26 votes, with Istanbul prevailing in a runoff, 49-45. On the second ballot, Tokyo thumped Istanbul 60-36.

After the vote, IOC members filed out of the hall at the Hilton Hotel complex to explain that the committee had made a smart and safe choice rather than taking a risk.

Tokyo's Olympic Plans

The proposed design for the Olympic Stadium was a part of Tokyo's bid for the 2020 Olympics. Tokyo

"The certainty was the critical factor," said Craig Reedie, chairman of the IOC's evaluation commission, who credited Japanese Prime Minister Shinzo Abe with addressing directly in his presentation continuing problems at the stricken Fukushima nuclear plant, more than two years after a tsunami triggered multiple meltdowns there. "The prime minister dealt with the one big issue." Mr. Reedie added that concerns over the Spanish economy hurt Madrid's bid. "I suspect the economy was a big factor."

As he walked out of the hall, Mr. Abe said, "I am very happy to share all of these emotions with the Japanese people."

Members said the final vote came down to a choice between a largely secure region and one of the safest big cities in the world and the capital of a country that shares a border with Syria and was simply too close to the turmoil in the Middle East.

"There were conversations about it," said James Tomkins, an IOC member from Australia and a former Olympic rower.

Hasan Arat, chairman of Istanbul's bid, compared the outcome to sport. "This is competition, and you have to respect the results." He declined to speculate on whether political turmoil in his region had harmed the bid.

Tokyo 1964 Summer Olympics

While traffic hurries along a wide road underneath, a new freeway is shown against a background of modern buildings in Tokyo, February 26, 1964. Japan is building fast; climbing industrially; living better than ever before and enjoying more leisure. But while the ruling class drives for more markets and money, ordinary Japanese talk of the need for disarmament and peace. (AP Photo) AP

Turkey's Prime Minister Recep Tayyip Erdogan, speaking to the Turkish press accompanying him in Buenos Aires, said his country respected the decision of the committee. "My only regret is that the Games were given to a country which has already organized the Olympic Games. Istanbul would have been a different kind of a city, a city which brings together many cultures and civilizations and connects Asia with Europe." Mr. Erdogan said Turkey may apply again in the future.

In Tokyo, where the announcement came around 5 a.m., cheers erupted from crowds gathered before dawn at public viewing venues. About 2,000 people had crowded into a gymnasium where Japan's women's volleyball team had famously rallied the nation with a surprise gold medal 49 years earlier. To some, Saturday's announcement seemed no less surprising, even if Tokyo had been regarded as the overwhelming favorite. "I thought Tokyo has a slim chance because of the Fukushima nuclear disaster," said Shingo Hayashi, a 32-year-old businessman who was among the celebrants in the gymnasium.

Tokyo packaged its bid as the safe one. Unlike in other nations, there was no discernible, organized domestic opposition, and indeed there was widespread enthusiasm—a contrast with Tokyo's bid for the 2016 games, which was undermined by a widespread domestic skepticism. Polls in 2009 showed then that slightly more than 50% of Tokyo residents wanted the games, compared with some recent surveys showing more than 90%.

A variety of factors explain the turnaround, including a nation determined to rebound from the 2011 triple disaster of a giant earthquake, tsunami and nuclear accident. Also, a popular new prime minister, Mr. Abe, personally backed the bid with a final last-minute pitch, unlike the government in 2009, which took a more hands-off approach.

Like other possible host countries, Japan's government finances are in tatters. In fact, its public debt is worth more than twice the size of its economy, the highest ratio in the developed world. But the debt is largely domestically held, the bond market is stable, rates are low, and there is no sign of any difficulty continuing to secure financing. In its pitch, Tokyo emphasized its financial stability, saying it already had a $4.5 billion reserve fund. With an estimated total budget of $7.4 billion, Tokyo's games would also be one of the cheapest in recent memory, undercutting Beijing in 2008 and London in 2012.

The one cloud that seemed to hang over the bid was the government's struggle to bring the stricken Fukushima nuclear plant under control, and the emergence of new problems in recent weeks — prominently covered in the international media—about the inability to contain tons of water contaminated with radioactive elements. Mr. Abe addressed that directly in his final pitch to the IOC members, and seemed to persuade them it wasn't a significant concern. "Let me assure you the situation is under control," Mr. Abe said. "It has never done and will never do any damage to Tokyo."

For the IOC, which has been pelted in recent months with reports of delays and difficulties in the run up to the Sochi Games in February and planning for Rio Janeiro in 2016, Tokyo was an opportunity to take a deep breath.

Jacques Rogge, president of the IOC, said Tokyo prevailed because of the high quality of its bid and also because of the experience of the bid team, which went through the process four years ago. "Tokyo has described itself as a safe pair of hands," Mr. Rogge said. "As a surgeon, that is something that appeals to me."

"We made the safe bet," said John Coates, an Australian member. Mr. Coates said Tokyo had strong support heading into the vote from Asia and Oceania, then benefited from European members who may not have wanted to support a Games in Madrid or Istanbul, which would harm the chances of a possible bid from other capitals such as Paris or Rome in 2024. "Tokyo is a safe, secure city, and there are major commercial advantages for the IOC with it being the third biggest economy in the world."

The Tokyo Games sets up a challenge for NBC, which paid $4 billion for the U.S. television rights to the Olympics from 2014 to 2020 and will now be featuring two consecutive Games with 13- and 14-hour time differences. Mark Lazarus, the chairman of NBC Sports, said the network was "very comfortable operating in that part of the world. The last time we were there in Beijing we did very well."

Tokyo's win didn't come as a surprise but the first-round results certainly were, as Madrid had been expected to make the final vote. Prince Albert of Monaco, an IOC member, said Spain's economic difficulties proved too large an obstacle, but he was stunned to see Istanbul defeat Madrid in a runoff, since few gave Istanbul a chance against Tokyo. It picked up only 10 votes from Spanish support from the first to the second round. "It's possible some European members have a more long-term strategy," he said, referring to hopes for another European capital in 2024.

Spanish Prime Minister Mariano Rajoy had sought to assure IOC members that his country could easily finance the games despite its deep recession, saying that 28 of the 35 Olympic venues had already been completed.

After the vote, he said in Buenos Aires: "Madrid is a city that was ready. A great effort was made but in life you win sometimes and lose others." He stopped short of pledging another Olympic bid after three successive failures.

Even Rafael Nadal, the No. 2 tennis player in the world and winner of the Beijing Olympic gold medal in 2008 for Spain, expressed his disappointment about the news.

"All the country, all the city of Madrid, worked a lot to have that chance, and for so many times already. So we feel that we deserve it," Nadal said following his match on Saturday at the U.S. Open tournament.

The U.S. is also planning a bid for 2024, which now sets up as a difficult competition. "We'll be a strong competitor," said Anita DeFrantz, an American IOC member. "But we are going to have to go up against the best."

Corrections & Amplifications The chairman of the International Olympic Committee's evaluation commission is Craig Reedie. An earlier version of this article misspelled Mr. Reedie's name.

—Joe Parkinson in Istanbul and Takashi Mochizuki in Tokyo contributed to this article.

This copy is for your personal, non-commercial use only. Distribution and use of this material are governed by our Subscriber Agreement and by copyright law. For non-personal use or to order multiple copies, please contact Dow Jones Reprints at 1-800-843-0008 or visit www.djreprints.com.